Due to the rapid development of the display technique, the advent of touch panel (TP) brings the user a more convenient life.
The touch panel comprises an Add-On touch panel and an In-Cell touch panel. In the In-Cell touch panel, a touch panel with a touch sensor (i.e., a touch driving electrode and a touch sensing electrode) is integrated in the display panel, and generally is arranged between the array substrate and the liquid crystal layer of the display panel. In the In-Cell touch panel, it is possible to realize a display touch panel which has the display and touch control function and is simply in structure.
The touch sensing for the In-Cell touch panel is conducted in a capacitance mode, which can be further divided into a self capacitance mode and a mutual capacitance mode. The self capacitance In-Cell touch panel has been widely applied due to its advantages of simple in fabrication and low power consumption. The touch control principle is to utilize the electrical field of the human body. When the user's finger is approaching a light output side of the display panel (and thus approaching the touch panel), the parasitic capacitance (Cp) between the touch driving electrode and the touch sensing electrode will vary in its magnitude. Whether a touch occurs can be determined by a terminal system which is connected with the touch driving electrode and the touch sensing electrode, and each position of touch point can be accurately determined, thus realizing the touch and display function.
In the self capacitance In-Cell touch panel, it is required to arrange the additional touch driving electrode and touch sensing electrode in the existing array substrate and the liquid crystal layer. This not only increases the number of patterning processes, which leads to increase in production cost, but also affects the light transmittance of the display panel.